Make your heart younger with exercise

A new study in mice may provide new clues into the cardiac benefits of exercise.

Researchers from Harvard University have determined that one way that exercise is beneficial is that it encourages the heart to build new muscle cells.

As we age, our hearts become less and less able to regenerate cells. For example, young adults have a small capacity for regenerating heart cells at around one per cent a year. After that, it’s negligible.

Because heart failure has been linked to losing heart cells, finding ways to remake them has the potential to prevent cardiac incidents.

The study

In the new study published in the journal Nature Communications, researchers took two groups of healthy mice and gave one group access to a treadmill.

“We wanted to know whether there is a natural way to enhance the regenerative capacity of heart muscle cells,” said Ana Vujic, one of the study authors. “So we decided to test the one intervention we already know to be safe and inexpensive: exercise.”

The treadmill mice ran around 5 km per day of their own accord, while the control mice stayed sedentary.

To measure heart regeneration, researchers gave the mice labelled chemical DNA. This labelled DNA was incorporated into the mice’s newly made cells, allowing the researchers to track it.

Results

After eight weeks, the results showed that the exercising mice had produced more than four and a half times more new heart muscle cells compared to the sedentary mice.

Furthermore, the researchers wanted to see if the same results were true with a heart attack victim. After giving the mice a simulated heart attack, they measured the mice’s cells again. The results showed that the exercising mice had an increase of heart tissue where new cells were made.

Now, obviously, mice physiology is very different to human physiology but it does provide evidence that exercise might serve a similar function in people. Further research can now be completed on the exact pathways — and exercise regimens — that increase heart health.

As Anthony Rosenzweig, one of the senior authors of the study, said:

“Maintaining a healthy heart requires balancing the loss of heart muscle cells due to injury or aging with the regeneration or birth of new heart muscle cells. Our study suggests exercise can help tip the balance in favour of regeneration.”